finding volume of gas

Iron reacts with excess steam asshown below. What volume of hydrogen , at 298K and 100kPa,is produced when 100kg of iron reacts with excess steam?

3Fe + 4H20 -----> Fe3O4 + 4H2

How do you do this ...im completely stuck.. please help
Thanks

Reply 1

Dogkicker91

Work out the moles of Iron with mass=moles x mr

From this work out the number of moles of Hydrogen

Put the number of moles into pV=nRT

Reply 2

DeanK2

You need to work out at the end of the reaction (assuming 100% yield) how much hydrogen there is.

You then use the fact that 1 mole of gas takes up 22.4 dm^3 of space, regardless of what the gas is.

EDIT: This is a standard result from pV = nRT

Reply 3

nathan00

3 moles of iron forms 4 moles of hydrogen gas.
can you work from there?

Reply 4

0zero0

Dogkicker91

Work out the moles of Iron with mass=moles x mr

From this work out the number of moles of Hydrogen

Put the number of moles into pV=nRT

i get 59201.24 L

does it look right??

Reply 5

DeanK2

0zero0

i get 59201.24 L

does it look right??

hmmmm

A litre isn't eactly a standard unit for quoting volumes. Stick with Pa.

EDIT: dm^3.

Reply 6

0zero0

DeanK2

hmmmm

A litre isn't eactly a standard unit for quoting volumes. Stick with Pa.

does the answer look right though?
im not sure as im doing such questions for the first time!

Reply 7

DeanK2

what is the mr of iron?

Reply 8

0zero0

DeanK2

what is the mr of iron?

55.8

Reply 9

Transatlanticdrawl_

When quoting your volumes in chemistry, always always use dm^3

Reply 10

Malsy

because iron there is 3 moles would it be 100 / 55.8 or (55.8 x 3) ?

that's the part i'm stuck on. other than that you'd find the number of moles using:

n = mass / Ar
n = 100 / 55.8 (i think)

= 1.792

then convert your units into SI units
100kPa = 100000 Pa.
298 K is fine
then use your gas equation to find volume

nRT/p

substitute in your numbers

1.792 x 8.31 x 298
/
100000

work that out...

unless, like I said I've gone TOTALLY wrong due to it being 3 moles of Iron..could anyone clear this up...

other than that i'm positive the working out is right....does that help?